Objective: To demonstrate a significant correlation between the Doppler waveform and blood flow volume in the assessment of valve efficiency. In particular the objective was to ratify use of the ‘area index’ of the wave form. Design: Pearson's correlation and zero line assessment were used. Using a phantom, multiple tests were performed so that a wide spectrum of flow volumes could be compared with corresponding Doppler waves. Setting: Private diagnostic imaging clinic with vascular surgical association. Main outcome measures: The hypothesis was that there should be a significant correlation between the Doppler wave and the blood flow volume and, in particular, the Doppler area. Results: The Doppler wave index EId demonstrated the highest correlation coefficient ( r = 0.97, p<0.01) when compared with the volume index EIV. Conclusion: While there is a strong correlation between EId and flow volume, additional study is needed to determine its place in the clinical setting.